Physics students at the UK's University of Leicester have concluded that a "real-life zombie outbreak" would all but eliminate humanity in just 100 days.
Ignoring more plausible threats like flu pandemic, Pumpkin Spice Latte poisoning, or tweet-triggered nuclear annihilation, Leicester students CT Davies, KJ Cheshire, R Garratley and J Moore constructed an epidemiological model of a zombie virus that gives each infected host a 90 per cent chance of turning an uninfected person into a zombie every day, during its brief 20-day life of shambling and flesh feasting.
The authors, having an apparent affinity for a preordained outcome, set the virus's contagion rate at about twice that of the Black Death. Otherwise, why bother?
The SIR model – where "S" stands for the number of susceptible individuals, "I" the number of infected individuals, and "R" the number of recovered individuals – suggests that after 100 days (an amount of time sufficient to make America great again) there would be 273 human survivors and a million zombies.
The students have written not one but two papers on the topic, perhaps because the first puts its finger on the scale by opting not to consider that humans might fight back and kill zombies – which would be mindless but not dead in this scenario. "Including [the possibility that humans may kill zombies] may give the humans a better chance at survival," the authors concede.
Given seven seasons of The Walking Dead, countless hours of training in zombie video games, films like World War Z, Night of the Living Dead, and Shaun of the Dead, and the non-trivial number of guns in the US (~300 million), counter-zombie activity deserves a variable in the equation.
The second paper allows for more familiar methods of zombie extermination, though the projected zombie kill rate – 0.1 per person per day, among the subset of people deemed capable of counter-zombie activity – seems remarkably low, at least with regard to cinematic norms.
It also allows for human reproduction, at a fairly enthusiastic pace. "Here we assume that at any given time half of the population are able to pair up and reproduce, giving birth to 1 baby every 3 years," the second paper says.
If humanity is allowed to fight back and reproduce, the second paper concludes, "we find that it is actually possible for our population to survive the zombie epidemic under these conditions..." ®